The OSI Managed-object Model

Abstract

The challenge facing the International Organization for Standardization (ISO) in the early eighties, in developing Open Systems Interconnection (OSI) protocol standards for network management, was to ensure that such protocols should, on the one hand, be standardised but, on the other, be capable of managing a myriad of resource types. ISO met the challenge by developing a single internationally-standardised carriage protocol (CMIP), and tools to produce information models that would reflect the resources being managed. Such an approach makes it possible for the same carriage protocol to carry management messages for many different types of resources. In developing its information modelling tools and services, ISO has adopted an object-oriented approach: the resources to be managed are modelled as managed objects or aggregates of managed objects. The managed-object model is similar to popular object-oriented programming-language models but it includes a number of features that reflect the special requirements of network management. These requirements include: asynchronous operation, active resources, a distributed environment, compatibility, and feature optionality. Fulfilling these requirements lead to the inclusion of concepts such as event-notification, multiple object-selection, packages, and allomorphism. The next generation of network-management standards will need to address the demands of large, multi-protocol, mutable networks. How these requirements might affect the evolution of the managed-object model and services is considered.